1. Field of the Invention
The present invention relates to an image forming apparatus for forming characters and images on a recording medium, such as a recording sheet, as it is being fed into the apparatus, and relates in particular to an image forming apparatus wherein a drive source is employed in common by multiple mechanisms, such as a recording medium feeding mechanism and an ink-jet head recovery mechanism for image forming.
2. Related Background Art
As the use in offices of personal computers, word processors and facsimile machines has become common, a variety of different image forming apparatuses have been produced and utilized to support automated office machines. Above all, since image forming apparatuses such as ink-jet printers, which form characters and images by ejecting ink onto recording media, provide superior balance among image quality, printing speeds, apparatus sizes and prices, and can easily produce colored images, image forming apparatuses have become especially popular and are presently employed in many fields.
These types of image forming apparatuses, specifically, ink-jet printers, generally include recovery mechanisms for removing viscous ink or dust attached to discharging orifices of ink-jet heads, and for thus maintaining a stable ink ejection function.
A well known recovery mechanism is a capping mechanism that, when printing is not in progress, uses a cap to cover the discharging orifice face of an ink jet head and to prevent ink from drying or evaporating, and that uses either a wiping mechanism, for which a blade is employed to wipe the discharging orifice face and remove attached ink, or a suction mechanism, for which suction is used to remove ink, through a cap, from the discharging orifices and from the surfaces in their vicinities. It should be noted that in this case the suction mechanism uses a pump to establish a negative pressure inside a cap covering the discharging orifice face and remove ink from the discharging orifices.
For a common image forming apparatus, a mechanism provided for supplying and feeding a recording medium, comprising an automatic paper supply mechanism, stores multiple recording media, such as recording sheets, and separates and separately supplies individual recording media; and a feeding mechanism, located downstream, synchronizes the feeding of the individual recording media with an image forming process. The automatic paper supply mechanism includes a paper supply roller that is rotated, under pressure, in contact with the topmost of the stacked recording media, and that separates and supplies the topmost recording medium. A friction member, located at the contact portion of the supply roller, generates sufficient friction to facilitate the supply of paper. The feeding mechanism includes a feed roller that rotates upon the application of a driving force produced by a drive source; a coupled roller that interacts with the feed roller and sandwiches the recording medium; and a paper path along which the recording medium is conveyed and passed between the rollers.
As is disclosed in Japanese Patent Application Laid-Open No. 11-233803 or No. 11-234697, in a well known conventional image forming apparatus, for multiple mechanisms that are driven by a drive source other than a carriage drive source, the transmission of the force produced by the drive source is changed in accordance with the location of a carriage on which a recording head is mounted. For example, in a configuration wherein the drive source is employed in common by a recovery mechanism and a paper supply mechanism, the driving force output to these mechanisms is switched in accordance with the location of the carriage, or in accordance with whether it is determined, consonant with the location of the carriage, a resisting operation is required at the paper supply mechanism.
Further, in an image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 11-231514, the cap in a recovery system is slid on and off and is opened or closed in accordance with the movement of the carriage.
Furthermore, in the configuration disclosed in Japanese Patent Application Laid-Open No. 11-138782, the wiping, the suction and the paper supply operations for the recovery system are performed using a third drive source that differs from a carriage drive source and a drive source for a recording medium feeding mechanism. In addition, in accordance with the location of the carriage when the recording head is mounted and the rotational direction and distance of the third drive source, the wiping operation and the suction operation are selectively performed by the recovery system, and one of multiple paper supply mechanisms is selected and driven.
However, the conventional configurations described in the publications originally change the drive source in accordance with the movement of the carriage, and therefore, they have the following problems.
According to the configurations disclosed in Japanese Patent Application Laid-Open No. 11-233803 and No. 11-234697, a comparatively complicated mechanism is required to change the drive source, and extra time is required to move the carriage to the switching position and to change the drive source. Further, in accordance with the position of the carriage, the switching position must be located outside the normal carriage movement range, and the size of the main body of the apparatus is increased, particularly in the direction in which the carriage is moved. These problems also apply to the configuration disclosed in Japanese Patent Application Laid-Open No. 11-231514.
In Japanese Patent Application Laid-Open No. 11-138782, since the third drive source is employed in common and is switched for the wiping operation, the suction operation and the paper supply operation, a complicated mechanism is required. Further, problems still exist in the time required for changing operations in accordance with the location of the carriage, and in downsizing and simplification and in cost reduction for the apparatus.
To resolve the above shortcomings, it is one objective of the present invention to provide an image forming apparatus having a simple configuration that can change a drive source used in common without requiring a switching operation in accordance with the movement of a carriage.
It is another objective of the present invention to provide an image forming apparatus, which employs a recording head to record data on a recording medium, comprising:
recovery means, for maintaining the recording performance of the recording head;
a first drive source, for driving feeding means for the recording medium; and
a second drive source, for driving supply means to supply the recording medium to the feeding means,
wherein the first drive source also serves as a drive source for a first drive mechanism, in the recovery means, by using a switching mechanism for changing the transmission of a drive force in accordance with a change in the operating direction of the first drive source, and
wherein the second drive source also serves as a drive source for a second drive mechanism, in the recovery means, by using a switching mechanism for changing the transmission of a drive force in accordance with a change in the operating direction of the second drive source.
It is an additional objective of the present invention to provide an image forming apparatus wherein the transmissions of drive forces, produced by the first and the second drive sources, are changed by employing switching mechanisms that change the drive forces in accordance with the operating directions of the respective drive sources, so that the transmission of the drive forces can be changed only by controlling the operating instruction for the drive sources, and at arbitrary timings.